I got the LS3 based heads from a place in BC, Canada. I bought them bare. They have Comp Cams valves, springs, titanium retainers and spring seats. They have a strong intake to exhaust ratio, 80%, so I went with a single pattern cam. It is a little on the small side, because I do a lot of cruising (5000 miles a summer) in the 1800 to 1900 rpm range and I want to get some decent fuel economy.